1. Field of the Invention
The present invention relates to a color image display device, and is particularly suitable for a display that uses a plasma display panel (PDP).
Recently, a high quality output image of a television set and a computer has been progressed, and a display device that can provide a display with high quality regardless of a type of the image such as a nature image or a character image.
2. Description of the Prior Art
As a display device having a large screen, a surface discharge format AC type PDP is commercialized. The surface discharge format means the format in which first and second display electrodes that become anodes and cathodes in display discharge for securing luminance are arranged in parallel on a front or a back substrate. A xe2x80x9cthree-electrode structurexe2x80x9d in which an address electrode is arranged so as to cross a pair of display electrodes is common as an electrode matrix structure of the surface discharge format PDP. One of the display electrodes (a second display electrode) is used as a scan electrode for selecting a display line, and address discharge is generated between the scan electrode and the address electrode, so that wall charge is controlled in accordance with contents of a display as an addressing step.
U.S. Pat. No. 5,825,128 has proposed a modified stripe partition structure of the three-electrode surface discharge type PDP for preventing discharge interference in the column direction (usually in the vertical direction) of the screen by meandering plural band-like partitions regularly that divide a discharge space in the row direction (i.e., the display line direction that is usually the horizontal direction) of the screen. Two neighboring partitions define a column space in which wide portions and narrow portions are arranged alternately. The position of the wide portion is shifted between neighboring columns, and a cell is formed in each of the wide portions. Red, green and blue fluorescent materials for a color display are arranged so that one color is disposed at each column space and a light emission color is different between neighboring column spaces. The arrangement form of the three colors is what is commonly called delta tri-color arrangement (or simply delta arrangement). The delta arrangement has a cell width larger than one third of a pixel pitch in the row direction. Therefore, compared with a square arrangement, the delta arrangement has a larger aperture ratio and realizes a higher luminance display. It is not necessary that the horizontal direction is the row direction. The vertical direction can be the row direction and the horizontal direction can be the column direction.
Conventionally, in a color image display using the delta arrangement PDP, each display line consists of cells each of which is selected fixedly from a cell column along an address electrode.
There was a problem that the following two phenomena cause an unnatural display.
(1) Since the positions of the neighboring cells are shifted in the vertical direction, a line in the horizontal direction is displayed in zigzag.
(2) A distance between the lighted cells becomes uneven when displaying a line inclined in the horizontal direction and in the vertical direction.
An object of the present invention is to provide an image display device that can secure predetermined display quality regardless of a type of an input image. Another object is to realize a pseudo interlace display, so as to improve resolution in the column direction.
A color image display device according to the present invention comprises a display device having a cell arrangement structure in which cell positions in the column direction are shifted from each other between neighboring cell columns among cell columns having the same lighting color and an image decision circuit for deciding which of plural predetermined types an input image is, and switches a form of the process for converting the image data into display data corresponding to the cell arrangement of the display screen in response to the input of the image data in accordance with the image decision result. An operation circuit is provided as data conversion process means. The cells are divided into groups considering the cell arrangement not uniformly to all cells of the display screen, and an appropriate operation such as a convolution process is performed for each group in different contents, or is performed only for some groups. The result of the operation is made display data, so that a phenomenon that a line looks zigzag can be reduced, or a pseudo interlace display can be realized. The operation includes a data process for selecting data of one or the other of neighboring lines in the input image as the display data.